Microprocessor controlled RF modulator apparatus

ABSTRACT

The microprocessor-controlled RF modulator apparatus will provide repeatable, controlled scintillation on a test bench generated low-power RF target waveforms for the purpose of providing a target returns with realistic radar cross section characteristics during testing of the F-16 (or any other) fire control radar. The microprocessor-controlled RF modulator apparatus is utilized in line between an RF target signal generator and the target horn to provide a variety of target situations for testing radar hardware and software.

STATEMENT OF GOVERNMENT INTEREST

The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon.

BACKGROUND OF THE INVENTION

The present invention relates broadly to an RF modulator apparatus, and in particular to a microprocessor-controlled RF modulator apparatus.

The state of the art of radar target signal simulators is well represented and alleviated to some degree by the prior arts apparatus and approaches which are contained in the following U.S. Patents:

U.S. Pat. No. 3,571,479 issued to Horattas et al on Mar. 16, 1971;

U.S. Pat. No. 3,783,172 issued to Bernstein on Jan. 1, 1974;

U.S. Pat. No. 3,792,475 issued to Smetana on Mar. 9, 1972;

U.S. Pat. No. 4,168,502 issued to Susie on Mar. 15, 1978;

U.S. Pat. No. 4,224,583 issued to Larken on Nov. 29, 1978; and

U.S. Pat. No. 4,327,417 issued to Zaczek on June 6, 1980.

The early prior art approach to radar target generation or simulation is shown in the prior art patents of Horattas et al and Bernstein. The Horattas et al patent is directed toward a digital electronic target generator wherein digitized radar targets are stored in a memory matrix where range is "bit" oriented and aximuth is "word" oriented. Each word in the matrix represents an azimuth line segment of a target on a radar display and the bit position within a matrix word represents the target range, each bit being the smallest range unit defined by the resolution of the display. A computer identifies the location of all targets in the display matrix and transfers the data to parallel-to-serial shift registers which output serial pulse trains representative of the target words. An output signal having analog characteristics is produced by summing the shift register output results and may be used in a simulator visual display.

The Berstein patent comprises a radar simulator apparatus which utilizes a general-purpose digital computer and a special interface which generates suitable video signals in response to the computer outputs to drive a radar set. In a radar simulator in which several different types of radar targets are simulated, the apparatus of this invention is used to generate the video signals which will display a plurality of mobile targets on the radar set. A limited number of such targets are displayed, and the characteristics of these targets are entered into the computer. Information representing the initial locations of the selected targets and their directions and speeds of movement is inserted into the computer from a remote station, and the computer performs the necessary navigational computations to continually determine the location of the radar set in the gaming area, the bearing of each of the targets from the radar set, and the bearing of the radar antenna at any time. The ranges of all of the targets on a particular bearing are entered by the computer into a register in the order of increasing range from the radar set. When the simulated radar antenna bearing agrees with the target bearing, the stored target ranges are read from the register and are converted into video signals to drive the radar set.

The Smetana, Zaczek and Susie patents respectively illustrate the present day approach of prior art target signal simulators which have been either extremely complicated in that they were controlled by a digital computer or limited to producing signals useful in testing short range or low PRF radar systems. The computer based systems were complicated due to the extensive programming which is required to generate the delays that correspond to the range of the simulated target and to calculate the pulse repetition frequency of the simulated target signal. The limited range of the simulators which did not use digital computers, resulted primarily from the fact that they provided no convenient means for generating a simulated target signal in which the time interval between adjacent pulses of the signal was less than the transit time to and from the simulated target.

The Larkin patent presents another novel approach to the field of radar target signal simulation through the use of a linear attenuator which uses a dc control current to change the RF resistance of PIN diodes that are in series and parallel with the load. As the control current changes, the RF resistance of the series diode will vary inversely, while the RF resistance of the parallel diode will vary directly thereby providing attenuation which changes linearly as a function of the control current through the series diode. The present invention is directed to a microprocessor-controlled RF modulator apparatus which provides RF target return signals to a fire control radar with realistic radar characteristics.

SUMMARY OF THE INVENTION

The present invention utilizes a microprocessor which is controllable in both attenuation range and frequency to amplitude modulate a test bench generated radar target return signal. The radar characteristic of the target are varied with respect to aspect angle, radar cross section and other physical parameter to provide a non-stable, time/amplitude varying signal which is representative of a true radar target.

It is one object of the present invention, therefore, to provide an improved microprocessor-controlled RF modulator apparatus.

It is another object of the invention to provide an improved microprocessor-controlled RF modulator apparatus that will generate repeatable, controlled scintillation to low-power waveforms.

It is another object of the invention to provide an improved microprocessor-controlled RF modulator apparatus with a realistic target simulation since the received target signal is amplitude modulated by the microprocessor unit.

It is another object of the invention to provide an improved microprocessor-controlled RF modulator apparatus which is controllable in both attenuation range and frequency.

It is another object of the invention to provide an improved microprocessor-controlled RF modulator apparatus wherein the degree of modulation can be controlled within minimum and maximum levels.

It is another object of the invention to provide an improved microprocessor-controlled RF modulator apparatus that generates a non-stable varying target return signal which is representative of a true air-to-air target.

These and other advantages, objects and features of the invention will become more apparent after considering the following description taken in conjunction with the illustrative embodiment in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating the use of the microprocessor-controlled RF modulator apparatus in a standard test set-up,

FIG. 2 is a block diagram of the microprocessor-controlled RF modulator apparatus according to the present invention,

FIG. 3 is a graphical representation of a variety of sample modulation waveforms,

FIG. 4 is a schematic diagram of the Z-80 central processor unit,

FIG. 5 is a schematic diagram of the 20K EPROM, memory unit,

FIG. 6 is a schematic diagram of the output latch unit and the digital to analog converter (DAC) unit, and,

FIG. 7 is a schematic diagram of the PIN diode attenuator unit.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Turning now to FIG. 1 there is shown a block diagram of a standard test set-up utilizing the microprocessor-controlled RF modulator apparatus 10 for testing a fire control radar unit 12. The system test bench unit 14 typically comprises an RF target generator unit 14a, a target controller unit 14b and an avionics simulator panel unit 14c. The test bench generated target signal is applied to the microprocessor-controlled RF modulator apparatus 10 wherein it is amplitude modulated and is controlled in both frequency and attenuation range. The modulated RF target return signal from the microprocessor-controlled RF modulator apparatus 10 is applied to the target horn 16. The target horn 16 is arranged to transmit the modulated RF target return signal to the fire control radar unit 12 which is under test.

The microprocessor-controlled RF modulator apparatus will provide repeatable, controlled scintillation to low-power RF waveforms for the purpose of testing the F-16 or any other fire control radar. The microprocessor-controlled RF modulator apparatus 10 is shown in FIG. 1 as installed in line between an RF target generator unit 14a and a target horn unit 16 to provide many added capabilities for testing the hardware and software of a fire control radar unit. This apparatus provides the user with a most realistic target simulation since the received target signal is amplitude modulated by the Z-80 microprocessor (which is shown in FIG. 2) and is controllable in both attenuation range and frequency. The scintillation (modulation) that can be provided can be square wave, swept square wave, triangle wave, sine wave or repeatable random noise at a number of frequencies and, in the case of the square wave functions, at a number of duty factors. The type of modulation, the frequency of the modulation and the duty factor are selected by setting the mini-lever switches which are respectively labelled Mode, Port 1 and Port 2 on the front panel of the microprocessor-controlled RF modulator apparatus. An operator may also control the degree of modulation by selecting the desired attenuation level with the Attenuation knob on the front panel. The minimum and maximum attenuation levels comprise a range of 0 to 60 db in steps of 0, 3, 10, 20, or 60 db.

A most effective use of the microprocessor-controlled RF modulator apparatus here at the Westinghouse Defense Center is to provide this controlled scintillation to a target signal that is generated by the F-16 system test bench. Now, instead of having the AN/APG-66 Fire Control Radar search, acquire and track a non-varying, non-oscillating, artificial target, the F-16 radar unit which is under test, must now respond to a simulated target signal whose generated aspect angle, radar cross section and physical characteristics are changing in a most realistic way. The amplitude modulation or scintillation, that is applied to the F-16 system test bench-generated RF target signal, provides a non-stable, varying RF target signal return which is a better representation of a true air-to-air target.

The versatility of the microprocessor-controlled modulator apparatus is especially evident in jamming scenarios since the radar no longer has a steady and solid target to detect and track, but instead, has to detect a target signal that is oscillating or modulating in the presence of a threat environment. This type of testing is valuable since, with the use of the microprocessor-controlled RF modulator apparatus, realistic target returns can be processed in the radar in both ECM and non-ECM environments.

Turning now to FIG. 2 there is shown a block diagram of the microprocessor-controlled RF modulator apparatus. Input ports unit 20 is operatively connected to the data select means which is not shown in FIG. 2 but is shown in FIG. 1 as the minilever switches that are labelled, Mode, Port 1 and Port 2. The input ports unit 20 which is connected to the Z-80 microprocessor unit 22 communicates the switch settings that control the output waveform parameters to the Z-80 central processor unit (CPU) 22. The Z-80 CPU unit 22 receives a 4 MHz clock signal from clock unit 26. An EPROM memory unit 24 which is a 20K memory unit is operatively connected to the Z-80 CPU unit 22. The EPROM memory unit 24 stores the waveform data and parameters which are utilized by the Z-80 CPU unit 22 to generate the simulated radar target test signal. The digital data which represents the radar target test signal is applied through output latch unit 28 to the digital to analog (DAC) unit 30 for conversion to an analog signal. The analog signal from the DAC unit 30 is applied to the amplitude control unit 32 which in response thereto generates a control voltage signal. The pin diode attenuator unit 34 utilizes the control voltage signal to modulate and structure the RF in signal into the selected waveform shape which becomes the RF out signal.

The microprocessor-controlled RF modulator apparatus utilizes the Z-80 CPU and its associated hardware and software to control the RF input signal that is received by the PIN diode unit. The PIN diode unit comprises a General Microwave D1958 PIN diode attenuator unit that provides a linear correspondence between a control voltage (0-6 VDC) and attenuation (0-60 dB). This control voltage which is converted to an analog signal by the digital analog converter unit and the amplitude control unit is the product of the microprocessor outputs and/or stored PROM memory data. Typical control voltage waveforms which may be generated by the microprocessor-controlled modulator apparatus are shown in FIG. 3 and are labelled (a) through (h). In Table I below there is shown the switch positions which provide the logic code to the Z-80 CPU to generate the digital signal that represents a particular output waveform.

                  TABLE I                                                          ______________________________________                                         The switch logic positions for the microprocessor-                             controlled RF modulator apparatus is shown as follows:                         Mode  Port 1  Port 2  Result                                                   ______________________________________                                         0     X       X       Not used                                                 1     X       X       0 dB Attenuation                                         2     0       X       RANDOM DATA - 125 Hz Switching                                                 Freq.                                                          1       X       RANDOM DATA - 80 Hz                                            2       X       RANDOM DATA - 45 Hz                                            3       X       RANDOM DATA - 20 Hz                                            4       X       RANDOM DATA - 15 Hz                                            5       X       RANDOM DATA - 2 Hz                                             6       X       RANDOM DATA - 1 Hz                                             7       X       RANDOM DATA - .5 Hz                                      3     0       X       6 Hz SQUARE                                                    1       X       35 Hz SQUARE                                                   2       X       80 Hz SQUARE                                                   3       X       150 Hz SQUARE                                                  4       X       180 Hz SQUARE                                                  5       X       250 Hz SQUARE                                                  6       X       350 Hz SQUARE                                                  7       X       650 Hz SQUARE                                                  X       0       97.5% Duty SQUARE                                              X       1       88.0% Duty SQUARE                                              X       2       73.0% Duty SQUARE                                              X       3       50.0% Duty SQUARE                                              X       4       27.0% Duty SQUARE                                              X       5       12.0% Duty SQUARE                                              X       6       2.5% Duty SQUARE                                         4     X       X       28.6-80 Hz SWEPT SQUARE                                                        in 2 seconds                                             5     0       X       .5 Hz SINE                                                     1       X       2 Hz SINE                                                      2       X       12 Hz SINE                                                     3       X       24 Hz SINE                                                     4       X       28 Hz SINE                                                     5       X       55 Hz SINE                                                     6       X       110 Hz SINE                                                    7       X       220 Hz SINE                                              6     0       X       2 Hz TRIANGLE                                                  1       X       10 Hz TRIANGLE                                                 2       X       20 Hz TRIANGLE                                                 3       X       40 Hz TRIANGLE                                                 4       X       50 Hz TRIANGLE                                                 5       X       83 Hz TRIANGLE                                                 6       X       125 Hz TRIANGLE                                                7       X       167 Hz TRIANGLE                                          7     X       X       Not used                                                 ______________________________________                                          (Note: X indicates that the switch position doesn't matter.)             

The microprocessor is an eight-bit, 40-pin device, which is operated by a 4 MHz clock and uses 20K of programmed data that is stored on ten (10) 2K EPROM memory chips. The remainder of the circuitry of the microprocessor-controlled RF modulator apparatus controls the buffering of the address and data lines, the I/O circuitry, and provides the gain and impedence matching which is required to drive the PIN diode attenuator.

In FIGS. 4 through 7, there is shown a complete schematic diagram of the microprocessor-controlled RF modulator apparatus wherein similarly designated points are commonly connected. The parts list for the schematic diagram of FIGS. 4 through 7 is given in Table 2 as follows:

                  TABLE 2                                                          ______________________________________                                         1 -    Z-80 Microprocessor (Zilog)                                             1 -    7406 MED                                                                1 -    74145 MED                                                               6 -    74244 MED                                                               2 -    74243 MED                                                               1 -    4 MHz oscillator                                                        10 -   2716 EPROMs Intel Corp.,                                                1 -    74100 MED                                                               1 -    DAC                                                                     1 -    PIN Diode Attenuator (Gen. Microwave D1958)                             3 -    Minilever Switches                                                      1 -    7400 MED                                                                1 -    3P2T switch                                                             1 -    2PlT momentary switch                                                   2 -    741 Op-amp MED                                                          1 -    5P wafer switch                                                         2 -    0-20K trim pots                                                         2 -    10K, 1/8 W resistor                                                     1 -    400 ohm, 1/8 W resistor                                                 1 -    22 ohm, 1/8 W resistor                                                  1 -    82 ohm, 1/8 W resistor                                                  1 -    220 ohm, 1/8 W resistor                                                 23 -   330 ohm, 1/8 W resistor                                                 ______________________________________                                    

In FIG. 4 there is shown a schematic diagram of the Z-80 microprocessor (CPU) and its associated circuitry. The elements of FIG. 4 can be related to the block diagram of FIG. 2 as follows. The Z-80 CPU of FIG. 2 comprises Z-80 microprocessor unit, the data line buffer units (74243); the address line buffer units (74244); the demultiplexer unit (74145) and its associated resistor array. In FIG. 5 there is shown the 20K EPROM memory unit which comprises ten 2K EPROM units (2716). In FIG. 6 there is shown the input ports unit of FIG. 2 which comprises the three minilever switches (Mode Sel, Port 1 and Port 2), the address line buffer units (74244) and the NAND gates (7400) which are associated with the buffer units. In FIG. 6 there is also shown the output latch unit of FIG. 2 which comprises the output latch unit (74100), the digital to analog converter unit (DAC) and the PIN diode attenuator. In FIG. 7 there is shown the amplitude control unit of FIG. 2 which comprises a pair of operational amplifier units (741) and its associated circuitry that includes a five position wafer switch as shown.

A desirable feature of the present apparatus is its programmability. The entire operation of the microprocessor-controlled RF modulator apparatus can be modified by changing the program of the EPROMs. The hardware does not need to be modified at all. The microprocessor-controlled RF modulator apparatus is rack-mountable and uses +5 V, +15 V and -15 V DC power.

The program memory is mapped as follows:

    ______________________________________                                         0000H-07FFH  (2K)      Program Executive                                       0800H-08FFH  (1K)      Sine Wave Simulation                                    0C00H-OFFFH  (1K)      Unused                                                  1000H-4FFFH  (16K)     Random Noise Simulation                                 ______________________________________                                    

                                      TABLE 3                                      __________________________________________________________________________     ER LINE                                                                              ADDR                                                                               B1 B2 B3 B4                Z80 ASSEMBLER I.L.S.O.                    __________________________________________________________________________     1                     ;*                                                       2                     ; MICROPROCESSOR CONTROLLED RF ATTENUATOR                3     0000                                                                               00                  NOP                                              4     0001                                                                               00                  NOP                                              5     0002                                                                               00                  NOP                                              6     0003                                                                               00                  NOP                                              7     0004                                                                               00                  NOP                                              8     0005                                                                               00                  NOP                                              9     0006                                                                               00                  NOP                                              10    0007                                                                               00                  NOP                                              11    0008                                                                               00                  NOP                                              12    0009                                                                               00                  NOP                                              13    000A                                                                               DB 01       START   IN     A,(1)                                     14    000C                                                                               3D                  DEC    A                                         15    000D                                                                               CA 34 00            JP     Z,0DB                                     16    0010                                                                               3D                  DEC    A                                         17    0011                                                                               CA F7 01            JP     Z,SAMPLE                                  18    0014                                                                               3D                  DEC    A                                         19    0015                                                                               CA 1C 01            JP     A,SQW                                     20    0018                                                                               3D                  DEC    A                                         21    0019                                                                               CA 83 00            JP     Z,SWP                                     22    001C                                                                               3D                  DEC    A                                         23    001D                                                                               CA 3B 00            JP     Z,SINE                                    24    0020                                                                               3D                  DEC    A                                         25    0021                                                                               CA EE 00            JP     Z,TRW                                     26    0024                                                                               D3 02       RNDM    IN     A,(2)                                     27    0026                                                                               DD 21 67 01         LD     IX,TBL2                                   28    002A                                                                               21 FF 3F            LD     HL,3FFFH                                  29    002D                                                                               FD 21 00 10         LD     IY,1000H                                  30    0031                                                                               C3 48 00            JP     S0                                        31    0034                                                                               3E 00       ODB     LD     A,O                                       32    0036                                                                               D3 10               OUT    (10H),A                                   33    0038                                                                               C3 0A 00            JP     START                                     34    003B                                                                               DB 02       SINE    IN     A,(2)                                     35    003D                                                                               DD 21 5F 01         LD     IX,TBL1                                   36    0041                                                                               21 FF 03            LD     HL,03FFH                                  37    0044                                                                               FD 21 00 0B         LD     IY,0900H                                  38    0048                                                                               16 00       GO      LD     D,O                                       39    004A                                                                               5F                  LD     E,A                                       40    004B                                                                               DD 19               ADD    IX,DE                                     41    004D                                                                               01 01 00            LD     BC,1                                      42    0050                                                                               D6 04               SUB    4                                         43    0052                                                                               FA 50 00    SKIP    JP     M,CEXT                                    44    0055                                                                               DD 7E 00            LD     A, IX)                                    45    0058                                                                               4F                  LD     C,A1                                      46    0059                                                                               C3 66 00            JP     OUT                                       47    0050                                                                               DD 7E 00    NEXT    LD     A,(IX)                                    48    005F                                                                               3D          LOOP    DEC    A                                         49    0060                                                                               CA 66 00            JP     Z,OUT                                     50    0063                                                                               C3 5F 00            JP     LOOP                                      51    0066                                                                               FD 7E 00    OUT     LD     A,(IY + 0)                                52    0069                                                                               D3 10               OUT    (10H),A                                   53    0068                                                                               FD 09               ADD    IY,BO                                     54    0060                                                                               ED 42               SHC    HL,BC                                     55    006F                                                                               FA 79 00            JP     M,CHJZ                                    56    0072                                                                               DB 02               IN     A,(2)                                     57    0074                                                                               D6 04               SUB    4                                         58    0076                                                                               C3 52 00            JP     SKIP                                      59    0079                                                                               DB 01       CHUZ    IN     A,(1)                                     60    0078                                                                               D6 05               SUB    5                                         61    0070                                                                               CA 3B 00            JP     Z,SINE                                    62    0080                                                                               C3 24 00            JP     RNDM                                      63    0083                                                                               01 00 00    SWP     LD     BC,O                                      64    0086                                                                               3E FF       SWL2    LD     A,OFFH                                    65    0088                                                                               D3 10               OUT    (10H),A                                   66    008A                                                                               11 FF FF            LD     DE,-1                                     67    008D                                                                               21 20 04            LD     HL,105BD                                  68    0090                                                                               09                  ADD    HL,BC                                     69    0091                                                                               19          SWL     ADD    HL,DE                                     70    0092                                                                               38 FD               JP     C,SWL                                     71    0094                                                                               00                  NOP                                              72    0095                                                                               00                  NOP                                              73    0096                                                                               00                  NOP                                              74    0097                                                                               00                  NOP                                              75    0098                                                                               00                  NOP                                              76    0099                                                                               00                  NOP                                              77    009A                                                                               00                  NOP                                              78    009B                                                                               00                  NOP                                              79    009C                                                                               00                  NOP                                              80    009D                                                                               00                  NOP                                              81    009E                                                                               00                  NOP                                              82    009F                                                                               00                  NOP                                              83    00A0                                                                               00                  NOP                                              84    00A1                                                                               00                  NOP                                              85    00A2                                                                               00                  NOP                                              86    00A3                                                                               00                  NOP                                              87    00A4                                                                               00                  NOP                                              88    00A5                                                                               00                  NOP                                              89    00A6                                                                               00                  NOP                                              90    00A7                                                                               00                  NOP                                              91    00A8                                                                               00                  NOP                                              92    00A9                                                                               00                  NOP                                              93    00AA                                                                               00                  NOP                                              94    00AB                                                                               00                  NOP                                              95    00AC                                                                               00                  NOP                                              96    00AD                                                                               00                  NOP                                              97    00AE                                                                               00                  NOP                                              98    00AF                                                                               00                  NOP                                              99    00B0                                                                               00                  NOP                                              100   00B1                                                                               00                  NOP                                              101   00B2                                                                               00                  NOP                                              102   00B3                                                                               00                  NOP                                              103   00B4                                                                               00                  NOP                                              104   00B5                                                                               00                  NOP                                              105   00B6                                                                               00                  NOP                                              106   00B7                                                                               00                  NOP                                              107   00B8                                                                               00                  NOP                                              108   00B9                                                                               00                  NOP                                              109   00BA                                                                               00                  NOP                                              110   00BB                                                                               00                  NOP                                              111   00BC                                                                               00                  NOP                                              112   00BD                                                                               00                  NOP                                              113   00BE                                                                               00                  NOP                                              114   00BF                                                                               00                  NOP                                              115   00C0                                                                               3E 00               LD     A,                                        116   00C2                                                                               D3 10               OUT    (10H),A                                   117   00C4                                                                               11 FF FF            LD     DE,-1                                     118   00C7                                                                               21 20 04            LD     HL,1056D                                  119   00CA                                                                               09                  ADD    HL,BC                                     120   00CB                                                                               19          SWL1    ADD    HL,DE                                     121   00CC                                                                               38 FD               JR     C,SWL1                                    122   00CE                                                                               0B                  DEC    BC                                        123   00CF                                                                               0B                  DEC    BC                                        124   00D0                                                                               0B                  DEC    BC                                        125   00D1                                                                               0B                  DEC    BC                                        126   00D2                                                                               0B                  DEC    BC                                        127   00D3                                                                               0B                  DEC    BC                                        128   00D4                                                                               0B                  DEC    BC                                        129   00D5                                                                               0B                  DEC    BC                                        130   00D6                                                                               0B                  DEC    BC                                        131   00D7                                                                               0B                  DEC    BC                                        132   00D8                                                                               0B                  DEC    BC                                        133   00D9                                                                               0B                  DEC    BC                                        134   00DA                                                                               0B                  DEC    BC                                        135   00DB                                                                               0B                  DEC    BC                                        136   00DC                                                                               0B                  DEC    BC                                        137   00DD                                                                               0B                  DEC    BC                                        138   00DE                                                                               0B                  DEC    BC                                        139   00DF                                                                               0B                  DEC    BC                                        140   00E0                                                                               0B                  DEC    BC                                        141   00E1                                                                               0B                  DEC    BC                                        142   00E2                                                                               0B                  DEC    BC                                        143   00E3                                                                               0B                  DEC    BC                                        144   00E4                                                                               0B                  DEC    BC                                        145   00E5                                                                               0B                  DEC    BC                                        146   00E6                                                                               0B                  DEC    BC                                        147   00E7                                                                               0B                  DEC    BC                                        148   00E8                                                                               78                  LD     A,3                                       149   00E9                                                                               E6 07               AND    07                                        150   00EB                                                                               47                  LD     B,A                                       151   00EC                                                                               18 98               JP     SWL2                                      152   00EE                                                                               DB 02       TRW     IN     A,(2)                                     153   00F0                                                                               57                  LD     D,A                                       154   00F1                                                                               06 00               LD     B,O                                       155   00F3                                                                               4F                  LD     C,A                                       156   00F4                                                                               DD 21 6F 01         LD     IX,TBL3                                   157   00F8                                                                               DD 09               ADD    IX,BC                                     158   00FA                                                                               DD 46 00            LD     B,(IX + 0)                                159   00FD                                                                               DB 02       TL4     IN     A,(2)                                     160   00FF                                                                               BA                  CP     D                                         161   0100                                                                               20 EC               JR     NZ,TRW                                    162   0102                                                                               3E 00               LD     A,0                                       163   0104                                                                               D3 10       TL3     OUT    (10H),A                                   164   0106                                                                               3C                  INC    A                                         165   0107                                                                               28 06               JR     Z,TL1                                     166   0109                                                                               48                  LD     C,B                                       167   010A                                                                               0D          TL2     DEC    C                                         168   010B                                                                               20 FD               JR     NZ,TL2                                    169   010D                                                                               18 F5               JR     TL3                                       170   010F                                                                               3E FF       TL1     LD     A,OFFH                                    171   0111                                                                               D3 10       TL6     OUT    (10H),A                                   172   0113                                                                               3D                  DEC    A                                         173   0114                                                                               28 E7               JR     Z,TL4                                     174   0116                                                                               48                  LD     C,B                                       175   0117                                                                               OD          TLS     DEC    C                                         176   0118                                                                               20 FD               JR     NZ,TL5                                    177   011A                                                                               18 F5               JR     TL6                                       178   011C                                                                               DB 04       SQW     IN     A,(4)                                     179   011E                                                                               E6 07               AND    007H                                      180   0120                                                                               4F                  LD     C,A                                       181   0121                                                                               DB 02               IN     A,(2)                                     182   0123                                                                               E6 07               AND    007H                                      183   0125                                                                               CB 27               SLA    A                                         184   0127                                                                               CB 27               SLA    A                                         185   0129                                                                               CB 27               SLA    A                                         186   012B                                                                               81                  ADD    A,C                                       187   0120                                                                               CB 27               SLA    A                                         188   012E                                                                               06 00               LD     B,O                                       189   0130                                                                               4F                  LD     C,A                                       190   0131                                                                               DD 21 77 01         LD     IX,TBL4                                   191   0135                                                                               DD 09               ADD    IX,BC                                     192   0137                                                                               DD 56 00            LD     D,(IX + 0)                                193   013A                                                                               DD 5E 01            LD     E,(IX + 1)                                194   013D                                                                               DB 02               IN     A,(2)                                     195   013F                                                                               47                  LD     B,A                                       196   0140                                                                               3E 00       SL5     LD     A,O                                       197   0142                                                                               D3 10               OUT    (10H),A                                   198   0144                                                                               7A                  LD     A,D                                       199   0145                                                                               4A          SL2     LD     C,D                                       200   0146                                                                               OD          SL1     DEC    C                                         201   0147                                                                               20 FD               JR     NZ,SL1                                    202   0149                                                                               3D                  DEC    A                                         203   014A                                                                               20 F9               JR     NZ,SL2                                    204   014C                                                                               DB 02               IN     A,(2)                                     205   014E                                                                               B8                  CP     B                                         206   014F                                                                               20 CB               JR     NZ,SQW                                    207   0151                                                                               3E FF               LD     A,OFFH                                    208   0153                                                                               D3 10               OUT    (10H),A                                   209   0155                                                                               7B                  LD     A,E                                       210   0156                                                                               4B          SL4     LD     C,E                                       211   0157                                                                               0D          SL3     DEC    C                                         212   0158                                                                               20 FD               JR     NZ,SL3                                    213   015A                                                                               3D                  DEC    A                                         214   015B                                                                               20 F9               JR     NZ,SL4                                    215   015D                                                                               18 E1               JR     SL5                                       216   015F                                                                               FF          TRL1    DEFB   OFFH                                      217   0160                                                                               4C                  DEFB   04CH                                      218   0161                                                                               09                  DEFB   9H                                        219   0162                                                                               02                  DEFB   2H                                        220   0163                                                                               01                  DEFB   1                                         221   0164                                                                               02                  DEFB   2                                         222   0165                                                                               04                  DEFB   4                                         223   0166                                                                               08                  DEFB   8                                         224   0167                                                                               08          TBL2    DEFB   8                                         225   0168                                                                               04                  DEFB   4                                         226   0169                                                                               02                  DEFB   2                                         227   016A                                                                               01                  DEFB   1                                         228   016B                                                                               01                  DEFB   1                                         229   016C                                                                               02                  DEFB   2                                         230   016D                                                                               04                  DEFB   4                                         231   016E                                                                               08                  DEFB   3                                         232   016F                                                                               00          TBL3    DEFB   0                                         233   0170                                                                               2E                  DEFB   46D                                       234   0171                                                                               16                  DEFB   22D                                       235   0172                                                                               0E                  DEFB   14D                                       236   0173                                                                               08                  DEFB   3D                                        237   0174                                                                               04                  DEFB   4D                                        238   0175                                                                               02                  DEFB   2D                                        239   0176                                                                               01                  DEFB   1D                                        240   0177                                                                               21          TBL4    DEFB   33D                                       241   0178                                                                               E1                  DEFB   225D                                      242   0179                                                                               41                  DEFB   65D                                       243   017A                                                                               C1                  DEFB   193D                                      244   017B                                                                               61                  DEFB   97D                                       245   017C                                                                               A1                  DEFB   1610                                      246   017D                                                                               B1                  DEFB   129D                                      247   017E                                                                               B1                  DEFB   129D                                      248   017F                                                                               A1                  DEFB   161D                                      249   0180                                                                               61                  DEFB   97D                                       250   0181                                                                               C1                  DEFB   193D                                      251   0182                                                                               41                  DEFB   65D                                       252   0183                                                                               E0                  DEFB   224D                                      253   0184                                                                               20                  DEFB   32D                                       254   0185                                                                               00                  DEFB   0D                                        255   0186                                                                               01                  DEFB   1D                                        256   0187                                                                               0E                  DEFB   14D                                       257   0188                                                                               62                  DEFB   98D                                       258   0189                                                                               1C                  DEFB   28D                                       259   018A                                                                               54                  DEFB   84D                                       260   018B                                                                               2A                  DEFB   42D                                       261   018C                                                                               46                  DEFB   70D                                       262   018D                                                                               38                  DEFB   56D                                       263   018E                                                                               38                  DEFB   56D                                       264   018F                                                                               46                  DEFB   70D                                       265   0190                                                                               2A                  DEFB   42D                                       266   0191                                                                               54                  DEFB   84D                                       267   0192                                                                               1C                  DEFB   28D                                       268   0193                                                                               62                  DEFB   98D                                       269   0194                                                                               0E                  DEFB   14D                                       270   0195                                                                               70                  DEFB   112D                                      271   0196                                                                               01                  DEFB   1D                                        272   0197                                                                               09                  DEFB   9D                                        273   0198                                                                               3E                  DEFB   62D                                       274   0199                                                                               12                  DEFB   18D                                       275   019A                                                                               35                  DEFB   53D                                       276   019B                                                                               1B                  DEFB   27D                                       277   019C                                                                               2C                  DEFB   44D                                       278   019D                                                                               24                  DEFB   36D                                       279   019E                                                                               24                  DEFB   36D                                       280   019F                                                                               2C                  DEFB   44D                                       281   01A0                                                                               1B                  DEFB   27D                                       282   01A1                                                                               35                  DEFB   53D                                       283   01A2                                                                               12                  DEFB   18D                                       284   01A3                                                                               3E                  DEFB   62D                                       285   01A4                                                                               09                  DEFB   9D                                        286   01A5                                                                               47                  DEFB   71D                                       287   01A6                                                                               01                  DEFB   1D                                        288   01A7                                                                               07                  DEFB   7D                                        289   01A8                                                                               2E                  DEFB   46D                                       290   01A9                                                                               0E                  DEFB   14D                                       291   01AA                                                                               28                  DEFB   40D                                       292   01AB                                                                               14                  DEFB   20D                                       293   01AC                                                                               21                  DEFB   33D                                       294   01AD                                                                               18                  DEFB   27D                                       295   01AE                                                                               18                  DEFB   27D                                       296   01AF                                                                               20                  DEFB   32D                                       297   01B0                                                                               14                  DEFB   20D                                       298   01B1                                                                               28                  DEFB   40D                                       299   01B2                                                                               0E                  DEFB   14D                                       300   01B3                                                                               2E                  DEFB   46D                                       301   01B4                                                                               07                  DEFB   7D                                        302   01B5                                                                               35                  DEFB   53D                                       303   01B6                                                                               01                  DEFB   1D                                        304   01B7                                                                               07                  DEFB   7D                                        305   01B8                                                                               2C                  DEFB   44D                                       306   01B9                                                                               0D                  DEFB   13                                        307   01BA                                                                               25                  DEFB   37                                        308   01BB                                                                               13                  DEFB   19D                                       309   01BC                                                                               1F                  DEFB   31D                                       310   01BD                                                                               19                  DEFB   25D                                       311   01BE                                                                               19                  DEFB   25D                                       312   01BF                                                                               1F                  DEFB   31D                                       313   01C0                                                                               13                  DEFB   19D                                       314   01C1                                                                               35                  DEFB   37D                                       315   01C2                                                                               0D                  DEFB   13D                                       316   01C3                                                                               2B                  DEFB   43D                                       317   01C4                                                                               07                  DEFB   7D                                        318   01C5                                                                               32                  DEFB   50D                                       319   01C6                                                                               01                  DEFB   1D                                        320   01C7                                                                               06                  DEFB   6D                                        321   01C8                                                                               24                  DEFB   36D                                       322   01C9                                                                               0B                  DEFB   11D                                       323   01CA                                                                               1F                  DEFB   31D                                       324   01CB                                                                               10                  DEFB   16D                                       325   01CC                                                                               1A                  DEFB   26D                                       326   01CD                                                                               15                  DEFB   21D                                       327   01CE                                                                               15                  DEFB   21D                                       328   01CF                                                                               1A                  DEFB   26D                                       329   01D0                                                                               10                  DEFB   16D                                       330   01D1                                                                               1F                  DEFB   31D                                       331   01D2                                                                               DB                  DEFB   11D                                       332   01D3                                                                               24                  DEFB   36D                                       333   01D4                                                                               06                  DEFB   6D                                        334   01D5                                                                               29                  DEFB   41D                                       335   01D6                                                                               01                  DEFB   1D                                        336   01D7                                                                               05                  DEFB   5D                                        337   01D8                                                                               1F                  DEFB   31D                                       338   01D9                                                                               09                  DEFB   9D                                        339   01DA                                                                               1A                  DEFB   26D                                       340   01DB                                                                               0D                  DEFB   13D                                       341   01DC                                                                               16                  DEFB   22D                                       342   01DD                                                                               12                  DEFB   18D                                       343   01DE                                                                               12                  DEFB   18D                                       344   01DF                                                                               16                  DEFB   22D                                       345   01EO                                                                               0D                  DEFB   13D                                       346   01E1                                                                               1A                  DEFB   26D                                       347   01E2                                                                               09                  DEFB   9D                                        348   01E3                                                                               1E                  DEFB   30D                                       349   01E4                                                                               05                  DEFB   5D                                        350   01E5                                                                               23                  DEFB   35D                                       351   01E6                                                                               01                  DEFB   1D                                        352   01E7                                                                               04                  DEFB   4D                                        353   01E3                                                                               16                  DEFB   22D                                       354   01E9                                                                               07                  DEFB   7D                                        355   01EA                                                                               13                  DEFB   19D                                       356   01EB                                                                               0A                  DEFB   10D                                       357   01EC                                                                               10                  DEFB   16D                                       358   01ED                                                                               0D                  DEFB   13D                                       359   01EE                                                                               0D                  DEFB   13D                                       360   01EF                                                                               10                  DEFB   160                                       361   01F0                                                                               0A                  DEFB   10D                                       362   01F1                                                                               13                  DEFB   19D                                       363   01F2                                                                               07                  DEFB   7D                                        364   01F3                                                                               16                  DEFB   22D                                       365   01F4                                                                               04                  DEFB   4D                                        366   01F5                                                                               19                  DEFB   25D                                       367   01F6                                                                               01                  DEFB   1D                                        368   01F7                                                                               FD 21 00 10 SAMPLE  LD     IY,1000H                                  369   01F8                                                                               21 FF 3F            LD     HL,3FFFH                                  370   01FE                                                                               FD 46 00            LD     B,(IY)                                    371   0201                                                                               DD 21 00 FF SCF     LD     IX,OFF00H                                 372   0205                                                                               FD 23               INC    IY                                        373   0207                                                                               2B                  DEC    HL                                        374   0208                                                                               31 00 00            LD     SP,0                                      375   020B                                                                               ED 7A               ADC    HL,SP                                     376   020D                                                                               CA F7 01            JP     Z,SAMPLE                                  377   0210                                                                               31 01 00            LD     SP,1                                      378   0213                                                                               FD 7E 00            LD     A,(IY)                                    433   0275                                                                               3D          JJ      DEC    A                                         434   0276                                                                               C2 75 02            JP     NZ,JJ                                     435   0279                                                                               DB 02               IN     A,(2)                                     436   027B                                                                               3D                  DEC    A                                         437   027C                                                                               3D                  DEC    A                                         438   027D                                                                               3D                  DEC    A                                         439   027E                                                                               3D                  DEC    A                                         440   027F                                                                               3D                  DEC    A                                         441   0280                                                                               CA BE 02            JP     Z,NOUT                                    442   0283                                                                               3E FF               LD     A,FFH                                     443   0285                                                                               3D          FF      DEC    A                                         444   0286                                                                               C2 85 02            JP     NZ,FF                                     445   0289                                                                               3E FF               LD     A,OFFH                                    446   028B                                                                               3D          KK      DEC    A                                         447   028C                                                                               C2 8B 02            JP     NZ,KK                                     448   028F                                                                               3E 2C               LD     A,2CH                                     449   0291                                                                               3D          LL      DEC    A                                         450   0292                                                                               C2 91 02            JP     NZ,LL                                     451   0295                                                                               DB 02               IN     A,(2)                                     452   0297                                                                               3D                  DEC    A                                         453   0298                                                                               3D                  DEC    A                                         454   0299                                                                               3D                  DEC    A                                         455   029A                                                                               3D                  DEC    A                                         456   029B                                                                               3D                  DEC    A                                         457   029C                                                                               3D                  DEC    A                                         458   029D                                                                               CA BE 02            JP     Z,NOUT                                    459   02A0                                                                               3E FF               LD     A, FFH                                    460   02A2                                                                               3D          GG      DEC    A                                         461   02A3                                                                               C2 A2 02            JP     NZ IGG                                    462   02A6                                                                               3E FF               LD     A, FFH                                    463   02A8                                                                               3D          HH      DEC    A                                         464   02A9                                                                               C2 AB 02            JP     NZ HH                                     465   02AC                                                                               3E FF       LD      A,OFFH                                           466   02AE                                                                               3D          NN      DEC    A                                         467   02AF                                                                               C2 AE 02            JP     NZ,NN                                     468   02B2                                                                               3E FF               LD     A,OFFH                                    469   02B4                                                                               3D          PP      DEC    A                                         470   02B5                                                                               C2 B4 02            JP     NZ PP                                     471   02B8                                                                               3E 5E               LD     A, EH                                     472   02BA                                                                               3D          QQ      DEC    A                                         473   02BB                                                                               C2 BA 02            JP     NZ, QQ                                    474   02BE                                                                               78          NOUT    LD     A,B                                       475   02BF                                                                               D3 10               OUT    (10H),A                                   476   02C1                                                                               DD 39               ADD    IX,SP                                     477   02C3                                                                               DA 01 02            JP     C,GOZ                                     478   02C6                                                                               C3 23 02            JP     ADD                                       479   02C9                                                                               ED 44       NEG     NEG                                              480   02CB                                                                               CB 20               SLA    B                                         481   02CD                                                                               0E 00               LD     C,O                                       482   02CF                                                                               5F                  LD     E,A                                       483   02D0                                                                               78          ADDNEG  LD     A,E                                       484   02D1                                                                               81                  ADD    A,C                                       485   02D2                                                                               D2 D6 02            JP     NC,NBYNEG                                 486   02D5                                                                               05                  DEC    B                                         487   02D6                                                                               4F          NBYNEG  LD     C,A                                       488   02D7                                                                               00                  NOP                                              489   02D8                                                                               D2 DC 02            JP     NC,NCYNEG                                 490   02DB                                                                               05                  DEC    B                                         491   02DC                                                                               4F          NCYNEG  LD     C,A                                       492   02DD                                                                               DB 02       LOOPNG  IN     A,(2)                                     493   02DF                                                                               3C                  INC    A                                         494   02E0                                                                               3D                  DEC    A                                         495   02E1                                                                               CA 6B 03            JP     Z,NEGOUT                                  496   02E4                                                                               3E 03               LD     A,3H                                      497   02E6                                                                               3D          AAA     DEC    A                                         498   02E7                                                                               C2 E6 02            JP     NZ,AAA                                    499   02EA                                                                               DB 02               IN     A,(2)                                     500   02EC                                                                               3D                  DEC    A                                         501   02ED                                                                               CA 68 03            JP     A,NEGOUT                                  502   02F0                                                                               3E 08               LD     A,BH                                      503   02F2                                                                               3D          BBB     DEC    A                                         504   02F3                                                                               C2 F2 02            JP     NZ,BBB                                    505   02F6                                                                               DB 02               IN     A,(2)                                     506   02F8                                                                               3D                  DEC    A                                         507   02F9                                                                               3D                  DEC    A                                         508   02FA                                                                               CA 68 03            JP     Z,NEGOUT                                  509   02FD                                                                               3E 14               LD     A,14H                                     510   02FF                                                                               3D          CCC     DEC    A                                         511   0300                                                                               C2 FF 02            JP     NZ,CCC                                    512   0303                                                                               DB 02               IN     A,(2)                                     513   0305                                                                               3D                  DEC    A                                         514   0306                                                                               3D                  DEC    A                                         515   0307                                                                               3D                  DEC    A                                         516   0308                                                                               CA 6B 03            JP     A,NEGOUT                                  517   030B                                                                               3E 2D               LD     A,2DH                                     518   030D                                                                               3D          DDD     DEC    A                                         519   030E                                                                               C2 0D 0D            JP     NZ,DDD                                    520   0311                                                                               DB 02               IN     A,(2)                                     521   0313                                                                               3D                  DEC    A                                         522   0314                                                                               3D                  DEC    A                                         523   0315                                                                               3D                  DEC    A                                         524   0316                                                                               3D                  DEC    A                                         525   0317                                                                               CA 6B 03            JP     Z,NEGOUT                                  526   031A                                                                               3E FF               LD     A,OFFH                                    527   031C                                                                               3D          EEE     DEC    A                                         528   031D                                                                               C2 1C 03            JP     NZ,EEE                                    529   0320                                                                               3E CE               LD     A,OCEH                                    530   0322                                                                               3D          JJJ     DEC    A                                         531   0323                                                                               C2 22 03            JP     NZ,JJJ                                    532   0326                                                                               DB 02               IN     A,(2)                                     533   0328                                                                               3D                  DEC    A                                         534   0329                                                                               3D                  DEC    A                                         535   032A                                                                               3D                  DEC    A                                         536   032B                                                                               3D                  DEC    A                                         537   032C                                                                               3D                  DEC    A                                         538   032D                                                                               CA 6B 03            JP     Z,NEGOUT                                  539   0330                                                                               3E FF               LD     A,OFFH                                    540   0332                                                                               3D          FFF     DEC    A                                         541   0333                                                                               C2 32 03            JP     NZ,FFF                                    542   0336                                                                               3E FF               LD     A,OFFH                                    543   0338                                                                               3D          KKK     DEC    A                                         544   0339                                                                               C2 38 03            JP     NZ,KKK                                    545   033C                                                                               3E 2C               LD     A,2CH                                     546   033E                                                                               3D          LLL     DEC    A                                         547   033F                                                                               C2 3E 03            JP     NZ,LLL                                    548   0342                                                                               DB 02               IN     A,(2)                                     549   0344                                                                               3D                  DEC    A                                         550   0345                                                                               3D                  DEC    A                                         551   0346                                                                               3D                  DEC    A                                         552   0347                                                                               3D                  DEC    A                                         553   0348                                                                               3D                  DEC    A                                         554   0349                                                                               3D                  DEC    A                                         555   034A                                                                               CA 6B 03            JP     A,NEGOUT                                  556   034D                                                                               3E FF               LD     A,OFFH                                    557   034F                                                                               3D          GGG     DEC    A                                         558   0350                                                                               C2 4F 03            JP     NZ,GGG                                    559   0353                                                                               3E FF               LD     A,OFFH                                    560   0355                                                                               3D          HHH     DEC    A                                         561   0356                                                                               C2 55 03            JP     NZ,HHH                                    562   0359                                                                               3E FF               LD     A,OFFH                                    563   035B                                                                               3D          NNN     DEC    A                                         564   0350                                                                               C2 5B 03            JP     NZ,NNN                                    565   035F                                                                               3E FF               LD     A,OFFH                                    566   0361                                                                               3D          PPP     DEC    A                                         567   0362                                                                               C2 61 03            JP     NZ,PPP                                    568   0365                                                                               3E 5E               LD     A,5EH                                     569   0367                                                                               3D          QQQ     DEC    A                                         570   0368                                                                               C2 67 03            JP     NZ,QQQ                                    571   036B                                                                               78          NEGOUT  LD     A,B                                       572   036C                                                                               D3 10               OUT    (10H),A                                   573   036E                                                                               DD 39               ADD    IX,SP                                     574   0370                                                                               DA 01 02            JP     C,GOZ                                     575   0373                                                                               C3 D0 02            JP     ADDNEG                                    576   0376                    END                                              __________________________________________________________________________     ASSEMBLER ERRORS = 0                                                           K/WESTINGHOUSE Z80 ASSEMBLER EC-02 VER. DATE 10/5/83 TIME OFF 15               CROSS REFERENCE                                                                LABEL                   VALUE        REFERENCE                                 __________________________________________________________________________     AA                      0239         -400                                      AAA                     02E6         -497                                      ADD                     0223         -386                                      ADDNEG                  0200         -483                                      BB                      0245         -406                                      BBB                     02F2         -503                                      CC                      0252         -413                                      CCC                     02FF         -510                                      CHUZ                    0079         -59                                       DD                      0260         -421                                      DDD                     030D         -513                                      EE                      026F         -430                                      EEE                     031C         -527                                      FF                      0285         -443                                      FFF                     0332         -540                                      GG                      02A2         -460                                      GGG                     034F         -557                                      GO                      0048         -33                                       GOZ                     0201         -371                                      H                       02A8         -463                                      HHH                     0355         -560                                      JJ                      0275         -433                                      JJJ                     0322         -530                                      KK                      0288         -446                                      KKK                     0338         -543                                      LL                      0291         -449                                      LLL                     033E         -546                                      LOOP                    005F         -43                                       LOOPNG                  02DD         -492                                      LOOPZ                   0230         -395                                      MEMORY        M         0000         0                                         NBARRY                  0229         -390                                      NBYNEG                  02D6         -487                                      NCARRY                  022F         -394                                      NCYNEG                  02DC         -491                                      NEG                     0209         -479                                      NEGOUT                  036B         -571                                      NEXT                    005C         -47                                       NN                      02AE         -466                                      NNN                     035B         -563                                      NOUT                    02BE         -474                                      ODB                     0034         -31                                       OUT                     0066         -51                                       POS                     021E         -383                                      PP                      0284         -469                                      PPP                     0361         -566                                      QQ                      02BA         -472                                      QQQ                     0367         -569                                      RNDM                    0024         -26                                       SAMPLE                  01F7         -363                                      SINE                    0038         -34                                       SKIP                    0052         -43                                       SL1                     0146         -200                                      SL2                     0145         -199                                      SL3                     0157         -211                                      SL4                     0156         -210                                      SL5                     0140         -196                                      SOW                     011C         - 178                                     STACK         S         0000         0                                         START                   000A         -13                                       SWL                     0091         -69                                       SWL1                    00CB         -120                                      SWL2                    0086         -64                                       SWP                     0083         -63                                       TBL1                    015F         -216                                      TBL2                    0167         -224                                      TBL3                    016F         -232                                      TBL4                    0177         -240                                      TL1                     010F         -170                                      TL2                     010A         -167                                      TL3                     0104         -163                                      TL4                     00FD         -159                                      TL5                     0117         -175                                      TL6                     0111         -171                                      TRW                     00EE         -152                                      __________________________________________________________________________

Other important areas in which the microprocessor-controlled RF modulator apparatus may be used are in developing NCTR algorithms and sideband/sidelobe track processing. Any periodic waveform that can be represented by a series of points (typically 1K or 2K of discrete quanta levels) can be accessed, read and used to modulate a testbench-generated target return. Engine sideband data, NCTR (Non-conforming target recognition) data and any irregular X-band returns of any type can be simulated easily, using existing hardware, with all modifications reserved to the executive algorithm and/or tables of programmed software.

Although the invention has been described with reference to a particular embodiment, it will be understood to those skilled in the art that the invention is capable of a variety of alternative embodiments within the spirit and scope of the appended claims. 

What is claimed is:
 1. A microprocessor-controlled RF modulator apparatus for testing a fire control radar comprising in combination:means for processing digital data which is operated by a four MHz clock means, said processing means utilizing said digital data to generate a digital target return signal, memory means for storing a predetermined amount of digital data, said memory means being eraseable and programmable, said memory means being operatively connected to said processing means, input port means for selecting a test target return signal, said input port means operatively connected to said processing means, means for converting said digital target return signal to a analog target return modulating signal, said converting means being operatively connected to said processing means, and, means for attenuating operatively connected to said converting means to receive said analog target return modulating signal therefrom, said attenuating means receiving an RF signal, said attenuating means in response to said analog target return modulating signal modulates said RF signal to provide a modulated test target return signal.
 2. A microprocessor-controlled RF modulator apparatus as described in claim 1 wherein memory means comprises a 20K EPROM memory unit.
 3. A microprocessor-controlled RF modulator apparatus as described in claim 1 wherein said converting means comprises an output latch means operatively connected to said processing means, said output latch means buffering data into and out of said processing means,a digital to analog converter means operatively connected to said output latch means to receive data therefrom, said digital to analog converter means converting said data to an analog signal, and, an amplitude control means operatively connected to said digital to analog converter means to receive said analog signal therefrom, said amplitude control means generating control voltage which is applied to said attenuating means to control the output signal therefrom.
 4. A microprocessor-controlled RF modulator apparatus as described in claim 1 wherein said attenuating means comprises a PIN diode attenuator.
 5. A microprocessor-controlled RF modulator apparatus as described in claim 1 further including an RF target generator to provide an RF signal to said microprocessor-controlled RF modulator apparatus, said test target return signal from said attenuating means being applied to an RF target horn, said RF target horn radiating said test target return signal to a fire control radar which is under test.
 6. A microprocessor-controlled RF modulator apparatus as described in claim 2 wherein said 20K EPROM memory unit comprises ten 2K EPROMS with their respective input lines connected in parallel and their respective output lines connected in parallel, both of which lines are respectively connected to said processing means.
 7. A microprocessor-controlled RF modulator apparatus as described in claim 6 wherein said converting means comprises an output latch means operatively connected to said processing means, said ouput latch means buffering data into and out of said processing means,a digital to analog converter means operatively connected to said output latch means to receive data therefrom, said digital to analog converter means converting said data to an analog signal, an amplitude control means operatively connected to said digital to analog converter means to receive said analog signal therefrom, said amplitude control means generating control voltage which is applied to said attenuating means to control the output signal therefrom, and, said attenuating means comprises a PIN diode attenuator. 